中东古新世高地饱压差油藏不稳定注水模型研究

油气田开发过程中一般考虑渗透率为常数，这对于压敏性储层并不适用。当地层压力下降时，压敏储层岩石会发生变形，孔隙空间减小从而减小渗透率。为了定量研究具有压敏特点的中东地区古新世高地饱压差油藏不稳定注水开发的数学模型，通过静水力学方法和单轴实验的方法，对中东地区古新世岩心渗透率随围压变化的规律进行实验研究；结合黑油模型的假设条件，推导了此类油藏不稳定注水渗流的全新数学模型。研究结果表明，中东地区古新世高地饱压差油藏渗透率与地层压力呈幂律关系，渗透率的降低将导致采收率降低且开发早期降幅最大，此类油藏宜采用不稳定注水方式开发。

Model study of unstable water injection for Middle East Paleocene reservoir with high formation-saturation pressure difference

During oil and gas field development, permeability is generally considered to be constant, which is not suitable for pressure-sensitive formation. Rock deforms once formation pressure drops, which always makes pore smaller and damages permeability. Mathematic model is studied to describe unstable water injection development for Middle East Paleocene reservoir with characteristics of pressure sensitivity and high difference of formation-saturation pressures. Based on hydrostatics and uniaxial test, Paleocene reservoir core from Middle East region with high difference of formation-saturation pressures is applied for experiment concerning the rule of permeability varying with confining pressure. Moreover, given the assumptions of conventional black oil model, a new mathematical model is set up for deformable-medium reservoir with high difference of formation-saturation pressures by unstable water injection. Research results show that for Middle East Paleocene pressure-sensitive reservoir, permeability has a power-law relationship with formation pressure, permeability decreasing leads to a lower recovery especially at early stage with a largest shrinkage, and unstable water injection is the best development way for this type of reservoir.